Rock Stars: Then and Now

"As you all know I had a very serious breakdown between December and March, and I had been advised by my doctor not to go on tour but didn't want to 'fail' or let anyone down," she explained to fans on her site before it was removed.

"Very stupidly I ignored his advice to my great detriment, attempting to be stronger than I actually am," she added.

"Smash" Goes Bollywood

Go behind the scenes with Katharine McPhee, Raza Jaffrey and Megan Hilty from NBC's "Smash" to see how a Bollywood-inspired dance is created for tonight's episode. Watch "Smash" Mondays at 10/9c. (Published Sunday, April 22, 2012)

Her decision to bow out of the music business followed her surprise cancellation of a performance in Munich Saturday.

"Any one have a job for a very clever woman with massive heart and courage, who adores people and has to escape music business as is very bad for her? Too much and too many long times away from home. All bad triggers for a woman with a mental illness. Can anyone come and take me home from Munich?" she tweeted at the time, the Irish Independent reported.

The 45-year-old — who rose to fame in the '90s with her hit "Nothing Compares 2 U" and to infamy when she tore up a picture of Pope John Paul II on "Saturday Night Live" — had just released a new record that was enjoying good reviews and sales.

O'Connor made headlines in December when she suddenly married, separated from and reunited with a drug counselor within a matter of weeks, The New York Times reported. They later separated again.